/usr/share/gazebo-7/media/rtshaderlib/ is in gazebo7-common 7.0.0+dfsg-2.
This file is owned by root:root, with mode 0o755.
..
/usr/share/gazebo-7/media/rtshaderlib/FFPLib_Common.glsl
/usr/share/gazebo-7/media/rtshaderlib/FFPLib_Fog.glsl
/usr/share/gazebo-7/media/rtshaderlib/FFPLib_Lighting.glsl
/usr/share/gazebo-7/media/rtshaderlib/FFPLib_Texturing.glsl
/usr/share/gazebo-7/media/rtshaderlib/FFPLib_Transform.glsl
/usr/share/gazebo-7/media/rtshaderlib/SGXLib_IntegratedPSSM.glsl
/usr/share/gazebo-7/media/rtshaderlib/SGXLib_NormalMapLighting.glsl
/usr/share/gazebo-7/media/rtshaderlib/SGXLib_PerPixelLighting.glsl
/usr/share/gazebo-7/media/rtshaderlib/SampleLib_ReflectionMap.glsl
/usr/share/gazebo-7/media/rtshaderlib/materials/
/usr/share/gazebo-7/media/rtshaderlib/materials/RTShaderSystem.material